Should i buy a whole new rear gear (2.73 with broken posi currently) or should i just buy new gears and an aftermarket posi? How much would the whole end cost? Just the gears and posi? These would all be plus installation. Also how long could this take? Anyone who has done this, your input is appreciated. Right now, if i floor it off the line, my tires don't even chirp. kind of sad after all the work i've done and it only spins one wheel. My friend has an 86 iroc with only an exhaust and his little one wheeler will spin through all of first at WOT. This is pretty discouraging. Thanks.

~Matt

 

A full posi rear axle assembly with decent gears from a boneyard will probably run you around $200-$300 (people have gotten them for less). It's fairly easy to change out (two people, floor jack, jack stands - about 4 hours including gear lube change and brake bleeding).

Posi carriers are about $350 new. Gears around $175-$200. Install kit $100. Labor around $150-$200. I've never priced a posi rebuild, but I'd guess around $200.

FWIW, spinning tires slow you down. Higher number ratio gears should get you going quicker, yes, but if you're chirping/spinning, you lack adequate traction and will get there later than if you weren't spinning.

 

So it would be better to hit the junk yard then. The only problem is that it is really hard to tell (i think) what gear ratios the yard will have. Is there a way to tell. $300 and 4 hours is better than $1050. Thanks five7kid. I just need to know how to tell which gear is which. I need the 7.5 in. right? 9 bolt? Sorry about all the questions. I don't want to get ripped off at the yard either. I know someone who was told they were getting 3.73 rears with posi and they turn out to be 3.08 opens. I know that if i have them jack the rear and i spin one tire, the other will spin the same way if it's posi. If it's open it will spin opposite. I think that's right. As for tire spin, i know me not spinning off the line is good because i go faster, but i'm tired of brakestands. Sometimes my brakes will be too good too and i'll have trouble doing them. Thanks again five7kid.

~Matt

 

Forget all the crap about RPO codes and jack this up and spin that, take the cover off and look. It's so easy and obvious that this is the only truly ultimately reliable and foolproof (me-proof?) way to tell what's in a rear end, it escapes me why it ever occurs to anyone to do anything else, or to even ask the question "how do I tell". Especially since the first thing you're going to do with some junk rear end, no matter how juicy the description the parts jockey gave you, is take the cover off and change the fluid.

Take the cover off and look - before you buy!!!!! You're going to be taking it off anyway.

If I were looking for the ultimate junk rear end, I'd be searching for 2 rear ends to combine, actually; a 6-cylinder 5-speed 90-92 one which will have 28-spline axles and has a high probability of having 3.42 gears in it, and a V8 disk brake 90-92 with posi, which will also have the late-model good brakes and 28-spline axles but a crap gear; and make one preemo one out of the 2 lesser ones.

 

I have a 9bolt on my t/a and it has a small tag on it that clearly states "Ratio 3.27". Look for a rear that's tagged or bring the calculater and count gears.

 

EFI V6 firebirds have 3.42's in 'em. but most are not posi.
There are tons of them. And they are likely to have not been abused as a Z28 or T/A will have. You can then buy a Powertrax Locker that replaces the guts, of the open rear dif easily in the drive way. Then rebuild the brakes and toss it in.
Get the street version of the Powertrax. Smooth operation.

http://www.powertrax.com/

 

Well gears came in today from summit. They are the wrong ones. They are for a 10 bolt. They do not carry gears for the 9 bolt so I will be visiting some of the websites above.

 

I also replied to your other message.

Here you go www.9bolt.com

Miles
Diff Solutions
www.9bolt.com